Yinon Rudich - Academia.edu (original) (raw)

Papers by Yinon Rudich

Atmospheric Chemistry and Physics Discussions, 2014

Proceedings of SPIE - The International Society for Optical Engineering

Clouds developing in a polluted environment have more numerous, smaller cloud droplets that can i... more Clouds developing in a polluted environment have more numerous, smaller cloud droplets that can increase the cloud lifetime and liquid water content. Such changes in the cloud droplet properties may suppress low precipitation allowing development of a stronger convection and higher freezing level. Delaying the washout of the cloud water (and aerosol), and the stronger convection will result in higher clouds with longer life time and larger anvils. We show these effects by using large statistics of the new, 1km resolution data from MODIS on the Terra satellite. We isolate the aerosol effects from meteorology by regression and showing that aerosol microphysical effects increases cloud fraction by average of 30 presents for all cloud types and increases convective cloud top pressure by average of 35mb. We analyze the aerosol cloud interaction separately for high pressure trade wind cloud systems and separately for deep convective cloud systems. The resultant aerosol radiative effect on...

Air particulate matter contains a wide range of substances which influence the physicochemical pr... more Air particulate matter contains a wide range of substances which influence the physicochemical properties of aerosol particles and thus their effects on atmospheric chemistry and physics, climate, and public health. Chemical reactions occurring on aerosol particles can transform these components and change their atmospheric and health effects. Gas-particle interactions generally involve multiple steps of mass transport and chemical reaction, and measurement data on the kinetics and products of these processes are sparse. Moreover, the terminology and formalisms applied for the interpretation and extrapolation of experimental results in different studies and aerosol systems are often incompatible. To provide a better basis for the analysis and comparison of laboratory measurement results and for their extrapolation and use in atmospheric models, a consistent and universally applicable terminology and mathematical framework for atmospheric aerosol surface chemistry and gas-particle in...

Reactions of organic aerosols can lead to changes in their hygroscopicity and their CCN activity.... more Reactions of organic aerosols can lead to changes in their hygroscopicity and their CCN activity. As a result, these processes may change organic aerosols' roles in local, regional and global air quality and climate. While most organic aerosols are secondary and hence already at least slightly processed in the atmosphere, it is quite possible that during their atmospheric lifetime they will continue to change. While several previous studies suggested increase of hygroscopicity, other studies have shown that reactions of the organic matter either do not affect hygroscopicity or even decrease it. We will present recent laboratory studies demonstrating how reactions of ozone and ammonia with aerosol particles containing model organic compounds (organic acids, alkenes) and complex organic matter (HULIS and fulvic acids) affect their hygroscopicity. Specifically, we will discuss under which conditions these reactions occur most efficiently (concentration ranges, exposure times, and h...

$Research paper thumbnail of Effective broadband refractive index retrieval by a white light optical particle counter$

The heterogeneous reactions between ammonium sulfate (AS), a proxy for inorganic ambient aerosol,... more The heterogeneous reactions between ammonium sulfate (AS), a proxy for inorganic ambient aerosol, and glycine, the most abundant amino acid in atmospheric aerosols with gas phase glyoxal were studied in terms of their optical, physical and chemical properties. The reactions were studied under different relative humidity (RH) conditions, varying from dry conditions, representative of arid regions (~19% RH) and up to 90% RH, typical for tropical conditions or in the vicinity of clouds. The product aerosols demonstrate a substantial growth in both geometric and optical extinction cross sections at λ=355nm under hydrated conditions, at a broad range of RH values of 35-90%. All reactions with gas phase glyoxal show a trend of increasing physical and optical growth relative to their initial size with decreasing seed aerosol size, from 100nm to 300nm, as well as with decreasing RH values from 90% to ~40%. This reaction occurs before deliquescence and may indicate the absorption of a few mo...

Geochmica et Cosmochimica Acta

One of the major uncertainties in the understanding of Earth's climate system is the interact... more One of the major uncertainties in the understanding of Earth's climate system is the interaction between solar radiation and aerosols in the atmosphere. This interaction is dependent on the physical and chemical properties of the aerosols and on the wavelength of the incident light. Aerosols exposed to high humidity areas will change their chemical, physical, and optical properties. To model hydrated aerosols, atmospheric chemistry models use the volume weighted mixing rule to predict the complex refractive index (RI) of aerosols when they interact with high relative humidity areas, and, in general, assume homogeneous mixing. The validity of these assumptions is explored. The extinction coefficient and growth factor of humidified aerosols, at 80% and 90% RH, and at 532 nm and 355 nm wavelengths was measured for size-selected aerosols of ammonium sulfate, peat (a lightly absorbing humic-like substance proxy), nigrosine (a black dye to model highly absorbing substances), and a mix...

Airborne fungi can cause a wide array of adverse responses in humans depending on the type and qu... more Airborne fungi can cause a wide array of adverse responses in humans depending on the type and quantity present. Since dose and human response is highly individual, the sensitivity of a person exposed is also an important consideration. The abundance of bioaerosols in the ambient air and their health impacts depend on the season and on the environmental conditions. In order to quantify and identify fungi bioaerosols' contribution to atmospheric aerosols and the impact to public health, it has been suggested to use chemicals that are typical of bioaerosols as biomarkers in chemical analysis of collected aerosols. An often used biomarker for determining the fungal biomass is ergosterol. Recently, Bauer et al. (2008) found that mannitol and arabitol concentrations are correlated with the fungal spore counts in atmospheric PM10. In this study, ergosterol, arabitol and mannitol were quantified in ambient aerosols collected in the Eastern Mediterranean region for 12 months in order to...

The optical properties of complex aerosols, important in determining their radiative forcing in t... more The optical properties of complex aerosols, important in determining their radiative forcing in the atmosphere and, subsequently, their impact on climate, are extensively examined. There is an abundance of natural and anthropogenic organic compounds in the atmosphere that can be released as primary aerosols or form secondary organic aerosols (SOAs) via photocchemical reactions with OH, NO3, and O3. SOAs can undergo further processing in the atmosphere with oxidative species, changing the chemical, physical, and optical properties of the particles. Absorbing aerosol components include nitrated aromatics, aromatic polycarboxylic acids, phenols, polycyclic aromatic hydrocarbons, and nitrated inorganics. Many of these species have been found in atmospheric particles. Some of them are strong absorbers at long UV wavelengths. Such aerosols may affect downward UV irradiances in urban location and may be important for predicting smog evolution in urban areas. It is possible that such specie...

The Journal of Physical Chemistry, 1996

The Journal of Physical Chemistry, 1995

ABSTRACT

Environmental science & technology, Jan 29, 2015

Inhalation of traffic-associated atmospheric particulate matter (PM2.5) is recognized as a signif... more Inhalation of traffic-associated atmospheric particulate matter (PM2.5) is recognized as a significant health risk. In this study we focused on a single ("sub-clinical response") exposure to water-soluble extracts from PM collected at a roadside site in a major European city, to elucidate potential components that drive pulmonary inflammatory, oxidative and defense mechanisms, and their systemic impacts. Intra-tracheal instillation (IT) of the aqueous extracts induced a 24h inflammatory response characterized by increased broncho-alveolar lavage fluid (BALF) cells and cytokines (IL-6 and TNF-α), increased reactive oxygen species production, but insignificant lipids and proteins oxidation adducts in mice' lungs. This local response was largely self-resolved by 48h, suggesting that it could represent a sub-clinical response to everyday-level exposure. Removal of soluble metals by chelation markedly diminished the pulmonary PM-mediated response. An artificial metal soluti...

Heterogeneous reactions of oleic acid aerosol particles with ozone are studied below 1% relative ... more Heterogeneous reactions of oleic acid aerosol particles with ozone are studied below 1% relative humidity. The particles have inert polystyrene latex cores (101-nm diameter) coated by oleic acid layers of 2 to 30 nm. The chemical content of the organic layer is monitored with ...

Proceedings of the National Academy of Sciences, 2015